公开(公告)号：JPH0991786A

公开(公告)日：1997-04-04

申请号：JP26645195

申请日：1995-09-20

Applicant: SONY CORP

Inventor： IWASAKI MASANORI

IPC: G11B11/10 ,  G11B7/09 ,  G11B11/105

Abstract: PROBLEM TO BE SOLVED: To improve reliability of a pickup and also obtain the optical pickup constituted in a small size while using the absolute minimum number of optical elements by providing a light emitter, an objective lens, a light separating means, a polarization separating means and photodetectors. SOLUTION: The light beam emitted from an element 11 is guided to a grating 12 to be divided into at least three beams. In a splitter 13, a half mirror surface is constituted as a polarization separating film and also is arranged by being inclined by 45 degrees with respect to the optical axis of a lens 14. Then, the film acieves separation between beams transmitted from the element 11 and return light beams. The lens 14 converges the beams passd through the splitter 13 on the desired track on a signal recording surface. Beams irradiated on the signal recording surface are again guided to the splitter 13 via the lens 14 as return light beams. Then, the beams reflected on the half mirror surface pass through an element 15 to be made incident on light receiving parts of photodetectors 16.

公开(公告)号：JPH0935352A

公开(公告)日：1997-02-07

申请号：JP20643295

申请日：1995-07-20

Applicant: SONY CORP

Inventor： IWASAKI MASANORI

IPC: G11B11/10 ,  G11B7/135 ,  G11B11/105

Abstract: PROBLEM TO BE SOLVED: To obtain an optical pickup device which is manufactured in a small size and easily with a simple constitution and in which the incident light quantity to photodetectors is made to be increased. SOLUTION: The laser beam irradiated from a laser element 22 is polarized to be irradiated by a polarizing prism 23 provided with a polarizing film 23a. Then, the polarized light beam is converged on the signal recording surface of a magneto-optical disk MO via a polarization hologram 12, a linear phase piece 13 and an objective lens 14 and then is reflected on the disk MO. The return light from the magneto-optical disk MO is separated into a normal light and an abnormal light by the polarization hologram 12 and the normal light is transmitted through the hologram as a 0-order light and the abnormal ligth is diffracted as ±1-order light beams. Moreover, a first photodetector 24 and a second photodetector 25 are provided at positions where the 0-order light of the return light is to be received and third photodetectors are provided at positions where the ±1-order light beams are to be received.

公开(公告)号：JPH0887782A

公开(公告)日：1996-04-02

申请号：JP24992694

申请日：1994-09-19

Applicant: SONY CORP

Inventor： IWASAKI MASANORI ,  HINENO SATORU

IPC: G11B11/10 ,  G11B11/105

Abstract: PURPOSE: To simplify and miniaturize constitution of a device and also to reduce cost of the device by separating a returned light separated with a separation optical system into three beams. CONSTITUTION: In the returned light separated with a double refraction diffraction grating type element, a O-order light beam transmitting a first area (a) and being a normal light and a O-order light beam transmitting a second area (b) and being an abnormal light are made incident on a center light receiving part. On the contrary, ±1st order light beams diffracted by the first area (a) and being the abnormal lights are respectively made incident on the light receiving parts positioned in the direction perpendicular to an optical axis with respect to the center light receiving part. Thus, signals such as the readout signal of a magneto-optical disk MO, focus error signal, tracking error signal and so forth are generated based on detection signals from respective light receiving parts of a photodetector 16.